Moderate versus deep hypothermic circulatory arrest for ascending aorta and aortic arch surgeries using open distal anastomosis technique

Background: There are two common strategies for brain protection during aortic arch surgeries, deep hypothermic circulatory arrest (DHCA) with retrograde cerebral perfusion (RCP) and moderate hypothermic circulatory arrest (MHCA) with antegrade cerebral perfusion(ACP). They are hotly debated, although the superiority of the latter is shown. We, therefore, have adopted MHCA with ACP for reconstruction cases and compared the hospital outcomes for these two circulatory arrest management strategies prospectively.Methods: From June 2015 to July 2017, a concurrent series of 43 patients (DHCA, 25; MHCA, 18) underwent ascending aortic ± aortic arch procedures for aortic aneurysm and dissection diseases using routine open distal anastomosis technique. The incidences of the three main types of operations performed (Bentall procedure (88.0% of DHCA vs 77.8% of MHCA), replacement (20% of DHCA vs 16.7% of MHCA) and interposition tube graft (12.0% of DHCA vs 16.7%of MHCA) did not reveal any statistical differences between the two groups. Similarly, rates of concomitant cardiac procedures (mitral valve repair and CABG, p-value of 0.664) were comparable.Results: All demographics were similar. Of note the prevalence of aneurysm pathology (76.0% of DHCA vs 72.2% of MHCA, p-value of 0.779). Total operative time (306.60 ± 25.31 vs 281.56 ± 30.06 min, p-value of 0.005), CPB time (208.04 ± 30.04 vs 179.83 ± 45.47 min, p-value of 0.019) and aortic cross-clamp time (150.20 ± 26.15 vs 125.56 ± 39.20 min, p-value of 0.018) were significantly higher in the DHCA group. Overall perioperative transfusion requirements were significantly lower in the MHCA group (72.0% of DHCA vs 55.6% MHCA, p-value 0.000. Postoperative outcomes were similar. Hospital mortality was 16.0% and 16.7% in DHCA and MHCA respectively. Similarly, stroke and reoperation for bleeding were similar (8.0% of DHCA vs 5.6%of MHCA, p-value of 0.756). Again, renal failure requiring dialysis rate was 12.0% in the DHCA group compared to 5.6% of MHCA (p-value 0.473).Conclusions: MHCA with ACP achieved very good and comparable results to DHCA with RCP for ascending and aortic reconstruction. Furthermore, MHCA significantly shortened total operative, cardiopulmonary bypass and ischaemic times and, basically, decreased transfusion requirements compared with the former strategy and consequently may lead to better patient's outcome